sneak

nouns

a person who is regarded as underhanded and furtive and contemptible
sneak
is derived from
sneaky
is a type of (narrower)
a person who is not pleasant or agreeable
disagreeable person, unpleasant person
someone who prowls or sneaks about; usually with unlawful intentions
prowler, sneak, stalker
is derived from
sneaky
someone acting as an informer or decoy for the police
canary, fink, sneak, sneaker, snitch, snitcher, stool pigeon, stoolie, stoolpigeon

verbs

to go stealthily or furtively
"..stead of sneaking around spying on the neighbor's house"
creep, mouse, pussyfoot, sneak
see also
sneak away
see also
sneak out
put, bring, or take in a secretive or furtive manner
"sneak a look"; "sneak a cigarette"
sneak
is a type of (narrower)
perform an action, or work out or perform (an action)
"think before you act"; "We must move quickly"; "The governor should act on the new energy bill"; "The nanny acted quickly by grabbing the toddler and covering him with a wet towel"
act, move
make off with belongings of others
abstract, cabbage, filch, hook, lift, nobble, pilfer, pinch, purloin, snarf, sneak, swipe
pass on stealthily
"He slipped me the key when nobody was looking"
slip, sneak

adjectives

marked by quiet and caution and secrecy; taking pains to avoid being observed
"a furtive manner"; "a sneak attack"; "stealthy footsteps"; "a surreptitious glance at his watch"
furtive, sneak, sneaky, stealthy, surreptitious